Combustion turbine power units



July 19, 1960 R. A. GILBERT 2,945,350

COMBUSTIONTURBINE'POWERUNITS Filed April 4; 195a r 2 Sheets-Sheet 1 INVENTOR Rounu: H. Gmsezf.

5v JYZZ'Jmqla-M 9 mm ATTolzNEw July 19, 1960 Filed April .4. 1956 R. A. GILBERT 2 ,945,350

COMBUSTION TURBINE POWER UNITS 2 Sheets-Sheet 2 5v am,% M WWW ATTOQNEYS United States Patent O to D. Napier & Son Limited, London, England, a British company Filed Apr. 4,1956, Ser. No. 576,101

Claims priority, application France Apr. 7, 1955 4 Claims. 01. 60-39-75) This invention relates to combustion turbine power units of the kind comprising'a turbine-driven air com pressor and a power turbine disposed at opposite ends of a combustion chamber or series of combustion chambers to which the compressor delivers combustion air and from which the products of combustion pass through the power turbine which is connected through reduction gearing (herein termed the power unit reduction gearing) to a power output shaft. This shaft may be connected, for example, to a propeller of an aircraft or a rotary wing system ofva helicopter, either directly or through further reduction gearing hereinafter termed the aircraft reduction gearing. The invention is applicable to such power units whether the compressor is driven by the power turbine or by a separate compressor-driving turbine.

The invention is particularly but not exclusively applicable to 'combustionturbine power units for driving the rotary wing systems of helicopters in which thepower unit is arranged with its axis vertical with the compressor below the turbine or turbines.

In a combustion turbine power unit of the kind referred to according to the present invention the power unit reduction gearing is arranged within a casing disposed on the side of the power turbine remote from the compressor and includes an input shaft coaxial with and directly driven by the power turbine while the power output shaft projects from the side of the casing remote from the power turbine, exhaust ducting is disposed on the side of the power turbine remote from the compressor and between the power turbine and the reduction gearing casing for carrying away the exhaust gases from the turbine or turbines, and a series of circumferenti'ally spaced stress-transmitting members connects the power unit reduction gear casing directly to the turbinecasing independently of the exhaust ducting.

In a preferred arrangement the exhaust ducting comprises two diametrically opposite ducts springing from a common annular chamber into which the exhaust outlet of the turbine casing opens, and the stress-transmitting members comprise four arms each extending radially from the power unit reduction gear casing to a part rigid with the turbine casing, two of these arms passing between the two exhaust ducts while the other two pass through tubular sleeves extending respectively across the interiors of the two exhaust ducts.

In one example of an aircraft of the helicopter type incorporating a power unit embodying the invention the power unit is arranged with its axis approximately vertical and with the power turbine above the compressor and with a rotary wing system disposed substantially coaxially with the output shaft of the power unit reduction gearing and driven therefrom.

The invention may be performed in various ways and one particular form of power unit embodying the invention and intended for driving the rotary wing system of a helicopter will now be specifically described by' way of example with reference to the accompanying drawings, in which:

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Figure 1 is a fragmentary side view of the helicopter, partly broken away to show the power unit mounted therein;

Figure 2 is a side view of the power unit on a larger scale; V

Figure 3 is a front view of the power unit looking in the direction of the arrow III in Figure 2; and

Figure 4 'isa cross-section taken on the line IVIV in Figure 2.

The combustion turbine power unit shown in the drawings comprises an axial flow air compressor, the upper end of the casing of which is shown at A having its air inlet at its lower end and delivering air into the lower ends of combustion chambers disposed within an enclosed casing A from which combustionchambers the combustion products pass to a power turbine, the casing of which is shown at A Secured to the upper end of the turbine casing A so that the exhaust opening of the turbine casing opens into it is exhaust ducting comprising an annular entry section B rigidly secured to a flange B of the turbine casing and from which spring a pair of upwardly-extending sections B through which the exhaust gases flow to two laterallyfacing outlets B Disposed above the exhaust ducting B, B is a power unitreduction gear casing C, the lower end of which lies in a space between the two duct sections B which for this purpose are formed with concave recesses B The power unit reduction gear casing C contains reduction gearing, for example of the epicyclic type, includingan input shaft C which enters the lower end of the casingC and is directly connected to the adjacent side of the power turbine, and an output shaft C coaxial with the input shaft C and disposed at the upper'end of the casing C where it is coupled through a coupling F with the input shaft F of aircraft reduction gearing contained in a casing F. From the aircraft reduction gear casing F the drive is transmitted on the one hand through an output shaft F to the rotary wing system G of the helicopter G and through another out-put shaft F to the tail rotor of the helicopter, which is not shown. The aircraft reduction gear casing F is rigidly connected to the air frame of the helicopter and is connected to the power unit reduction gear casing C through a torque transmitting coupling C which is not capable of supporting appreciable weight but which transmits torque reaction from the power unit reduction gear casing C to the air frame through the aircraft reduction gear casing F.

The power unit reduction gear casing C is connected to and supported from the upper end of the turbine casing A by four link assemblies each comprising a bracket D. The feet of the brackets D are supported by the flange B of the turbine casing. At the upper side of the brackets D are pin connections D by which are connected to the brackets D the outer ends of four radial arms D the inner ends of which are secured to the power unit reduction gear casing C. Two of the arm-s D pass through V-shaped gaps B between the two duct sections B while the other two arms pass through tubular housings B extending across the interiors of these duct sections.

Stifiening plates B connect the two duct sections B together at points where these duct sections are sufliciently wide to enable the stiffening plates B to clear the power unit reduction gear casing C.

The weight of the power unit is supported by structural members G of the helicopter air frame by means of struts G and G the upper ends of which are connected to brackets G rigidly connected to the power unit. The axes of the struts G and G intersect approximately at the centre of gravity H of the power unit.

The weight of the power unit reduction gear casing C and the parts which it contains is transmitted by the arms t 3, D and the brackets D to the turbine casing A and thence to'the supporting struts'G and owns the at? frame members G but the torque reaction of the power unit reduction gear casing is transmitted to the air t the out;

tio products therefrom, a casin'gfcontaining' said power turbine, said turbine casing having .an inlet 'sjidejadja {it said combustion chamber and an exhaust side a' ay from said combustion chamber, a reduction gear 'ror m p rt of said power unit, a casing containingsaidpoyye'r unit reduction gear disposed on'the exhaust s'ideofsaid turbiiie', casing and having an input side adjacent said turbine cas ng output'side; away from said turbine casing,

unit reduction gear casing and which is connected'to said power turbine, an output shaft projecting from the output side oifI said power unit reduction gear casing, exhaust d rig disposed on the exhaust s-ide' of said tnr ne casinig bet ween said turbine casing and said poweif'ufiit reduction gear casing, and a plurality of circumierentially spa ed stres s transmitting'members connecting sai power, un t reduction gear casing directly to said turbine casing independently of said exhaust ducting.- i T combustion turbine power unit according to of said combustion chamber CQ ififielyecotilblls an nput shaft which enters the input side of said power r as? claim 1 in which said exhaust ducting comprises a comriioifanniilar exhalisf' chainher ""ofi th'e i eifiaii's't smear said turbine casing, two diametrically opposite ducts springing from said common annular exhaust chamber, and tubular sleeves extending transversely across the interiors of said two exh'aiistduc ts, and in which said stress-transmitting members comprise, four arms, each extending-radialIy'Trom said power unit" reduction" gear casing, two ofithesefour arms passing between'sai'd two opposite exhaust ducts and theothertvvo (if saidarrns passing through said tubular sleeves.

3. A combustion turbinopower unit according to claim 2 in which there arefo'ur' brackets rigidly secured to said turbinec'asing, and means connecting said brackets to said radially extended arms. A r

4. A combustion turbine power unit according to claim 1, in which said stress-transmitting members comprise. four, arms each extending radially. and, atright an toj'eaclt other-from saidpoweitflinit. red tion gear ad as, and brackets, connecting nie'oateir extremities. of. said radially extending" to said turbine casin said 'ng girl with said turbine/casings in the Cir? "tion but cap ble, of movement in the.

iaison; Qitsfl n h fi e of his aten a UNITED STATES, P Tn s 2,514,206

Perry. July 4, 1 950 2,531,623 Campbell Q. Jan. 9; 1951 2,626,766 McDonald 'Ian. 21; 1953 26826 1 5 Fletcher Sept;. 21, 1954 r FOREIGlSI PATENTS 1,022,081 Fr nce May29, 1253 F ance 'linjimos 

